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Published on: April 30, 2014
Myosin regulatory light chain expression in trout muscle
Megan E Donato1, Jonathan Schiavi, Alexis D Ulerich
1Department of Biology, Widener University, Chester, Pennsylvania 19013, USA.
Summary
The slow myosin light chain (sMLC2) isoform varies along the trout body, influencing muscle contraction speed in young parr. This variation was not observed in older smolts, suggesting developmental changes in muscle regulation.
Area of Science:
- Muscle physiology
- Molecular biology
- Fish biology
Background:
- Muscle contractile properties exhibit variations based on fiber type, body location, and developmental stage.
- Rainbow trout myotomal muscle shows faster contractile properties anteriorly, with associated changes in troponin T and parvalbumin expression.
- Myosin heavy chain expression is uniform longitudinally in trout, indicating other myosin components regulate contractile variations.
Purpose of the Study:
- To investigate the role of the regulatory myosin light chain (MLC2) in modulating longitudinal variations of contractile properties in rainbow trout myotomal muscle.
- To determine if different MLC2 isoforms (slow and fast) contribute to the observed differences in muscle activation and relaxation along the trout body.
- To assess the expression patterns of MLC2 isoforms in relation to age (parr and smolt) and muscle type (red and white).
Main Methods:
- Cloning and sequencing of two MLC2 isoforms from rainbow trout muscle.
- Real-time quantitative polymerase chain reaction (qPCR) to measure the relative expression of slow (sMLC2) and fast (fMLC2) isoforms.
- Analysis of MLC2 isoform expression in red and white muscle from different body positions of parr and smolt trout.
Main Results:
- Longitudinal variations in sMLC2 expression were detected in young trout parr, but not in older trout smolts.
- No longitudinal variation was found for the fMLC2 isoform in either age group.
- The observed differences in sMLC2 expression in parr correlated with shifts in muscle contractile properties.
Conclusions:
- The slow myosin light chain (sMLC2) isoform plays a role in the longitudinal modulation of muscle contractile properties in juvenile rainbow trout (parr).
- Developmental stage influences the expression patterns of MLC2 isoforms, with sMLC2 variation diminishing in older smolts.
- MLC2 isoforms, particularly sMLC2, are key molecular components contributing to the functional regionalization of trout swimming muscle.
